1. Field
The following description relates to a method and a system for implementing the wind information on the sea, that is, the sea-surface wind information, from satellite observation.
2. Description of the Related Art
The sea-surface wind information is the very important information in various fields including preventive activities against a disaster, such as typhoon. For example, the sea-surface wind information can be utilized for the wind energy industry and is the very important information in marine activities including the fishery. In general, since the sea-surface wind strength is very closely associated with a physical change in the sea level resulting from it, a physical relation between them is derived to indirectly obtain the magnitude of the sea-surface wind. The sea-surface wind can be measured by direct observation using a buoy data or a ship, but it is impossible to monitor and observe the wide sea substantially in quasi-real time, and it can be said that only satellite observation is the only way to do so. In general, in order to observe the magnitude of the sea-surface wind by a satellite, sensors that can observe a wavelength range of microwave are needed, such as AMSR-E (Advanced Microwave Scanning Radiometer), SSM/I (Special Sensor Microwave/Imager), TMI (Tropical Microwave Imager).
The physical state of the sea level has a very important effect on the emissivity of the sea level. In general, the sea has characteristics of low emissivity and high reflectivity. The wind on the sea level is one of main factors that increase the reflectivity and emissivity to change energy observed by a satellite.
Many inventors have studied the characteristics for a long time, and the characteristics of sea-surface wind have been detected using an active microwave sensor, such as ASCAT, QUICKSCAT or by mounting a passive microwave sensor, such as SSM/I, AMSR-E, TMI on a satellite. Most of the studies have used a forward model based on very many known information items including the characteristics of wind and the sea level. However, these techniques have revealed a limit in obtaining the sea-surface wind information and have a problem with accuracy.